Graphical User Interface and Teaching Aid for Moment Curvature Analysis Open Access
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Moment Curvature Analysis Program (MCAP) has been developed for establishing moment-curvature analyses using an interface between a MATLAB® Graphical User Interface (GUI) and the finite element program Open System for Earthquake Engineering Simulation (OpenSees). The MATLAB® GUI was developed with the main goal of facilitating the use and interpretation of OpenSees. The combination of these two software programs provides a user friendly interface that can be used to supplement classroom instruction and enhance learning the response of sections using accurate nonlinear material stress-strain relationships. MCAP was primarily developed within a framework that guides the user through a logical sequence of steps for determining the moment and rotation capacity of commonly used structural sections. The simplicity of its use and its framework makes it particularly suitable as a teaching aid for graduates and undergraduates to analyze irregular and commonly used structural sections. Moment-curvature relationships are of primary importance in evaluating the nonlinear behavior of sections, members and structural systems.Some features of MCAP can be summarized as follows: (1) MCAP has been extended to analyze rectangular, circular and user defined arbitrary shape sections. (2) The development of a GUI interface for a user defined arbitrary shape section is significant as a teaching aid since most Moment-Curvature programs do not allow the user to define and analyze sections other than rectangular and circular sections. (3) MCAP also has the capability to perform a Moment-Curvature analysis on a rotated rectangular section.To further enhance classroom instruction a supplementary moment-curvature program was also implemented using MATLAB®. In its present form, this supplementary program can be used by users in tracing the programming steps required to develop a moment curvature analysis and subsequent load deformation response of rectangular reinforced concrete sections. One of the innovative features in the programming of this supplementary program is the implementation of a linear relationship between the curvature and the strains in the extreme steel fibers. To the best knowledge of the author, this linear relationship has not been previously used in encoding the moment curvature program. The main implication of this relationship is a significant decrease in the number of iterations required for convergence.Future developments for MCAP include a pile analysis module and expanding the program to perform a pushover analyses for reinforced concrete members. The implementation of a FRP confined section module is also being developed with an immediate application to the retrofit of circular and rectangular concrete sections. Further research on the relationship between the curvature and the strains in the extreme steel fibers is a future development that MCAP can help accomplish.